Liquid samples are analyzed for many different substances contained within the samples in a wide variety of industries. Such industries include but are not limited to biomedical research, clinical chemistry, environmental analysis, forensics, toxicology, pharmacology, petrochemicals, etc. Most laboratories employ devices for handing liquid samples. There is a need for devices that are capable of efficiently absorbing a liquid sample. Such absorbed samples may be analyzed soon after collection or may be transferred for subsequent analysis at a convenient time or location. There is a need for such devices to be capable of storing a sample until the time for analysis, when the device must release the sample.
Most current sampling devices require a large amount of a sample, such as blood drawing tubes. With the recent development of mass spectrometry, the detection sensitivity has been improved and amount of sample needed for detection is significantly reduced. In some situations, it is difficult to obtain a large amount of blood, such as from a small experimental animal, a newborn or elderly individuals with vascular problems. What is needed are liquid sampling devices that can collect relatively small amounts of a sample (less than 1 ml) and preserve the sample for a prolonged period.
Yet another drawback for most common sampling devices is that they require low temperature preservation. If a device can preserve the sample in an ambient temperature, it will reduce the cost and the chance for sample degradation. Whatman dry blood cards have been used in sample collection. However, the dry blood cards are open systems, the sample may be contaminated during sample storage, or sample transport process by the package materials, adsorption and human error. The dry blood cards also need to have a separate puncture device, a liquid transfer device and a cutting device to collect sample and release the sample. Multiple steps increase the chances of human error and contamination. Accordingly, there is a need for sample collection devices that can puncture the target, collect a small amount of a liquid sample, preserve the sample, treat the sample and release the sample to the downstream analytical devices in a closed system.